Pure Virtual Function in OOPs

 #include <iostream>

using namespace std;

// abstract class

class Shape {

public:

    virtual void draw() = 0; //abstract fnx, pure-virtual fnx

};

class Circle : public Shape {

public:

    void draw() {

        cout << "draw circle\n";

    }

};

class Square : public Shape {

public:

    void draw() {

        cout << "draw square\n";

    }

};

int main() {

    Circle c1;

    c1.draw();

    Square sq1;

    sq1.draw();

    return 0;

}

output:

draw circle

draw square